x86/vdso: Fix building on big endian host

We need to call GET_LE to read hdr->e_type.

Fixes: 57f90c3d ("x86/vdso: Error out if the vDSO isn't a valid DSO")
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: linux-next@vger.kernel.org
Link: http://lkml.kernel.org/r/20160929193442.GA16617@gate.crashing.org


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>